Influence of molar ratio of citric acid to metal ions on preparation of La0.67Sr0.33MnO3 materials via polymerizable complex process

2005 ◽  
Vol 25 (16) ◽  
pp. 3611-3618 ◽  
Author(s):  
Wein-Duo Yang ◽  
Yen-Hwei Chang ◽  
Shu-Hui Huang
Keyword(s):  
Citric Acid ◽  
Metal Ions ◽  
Molar Ratio ◽  
Complex Process

Influence of Molar Ratio of Citric Acid to Metal Ions on Structure, Microstructure and Electrical Transport Properties on Nanosized La0.85Na0.15MnO3

2015 ◽  
Vol 1107 ◽  
pp. 261-266
Author(s):  
Kean Pah Lim ◽  
Kuen Hou Cheong ◽  
Abdul Halim Shaari ◽  
Mansor Hashim ◽  
Albert Han Ming Gan ◽  
...  
Keyword(s):  
Citric Acid ◽  
Metal Ions ◽  
Grain Boundaries ◽  
Transport Properties ◽  
Electrical Transport ◽  
Perovskite Phase ◽  
Hexagonal Structure ◽  
Molar Ratio ◽  
High Resistivity ◽  
Electrical Transport Properties

In this paper, nanosized La0.85Na0.15MnO3 (LNMO) has been synthesized via sol-gel method by involving two major steps, first the complexation of citric acid (CA) with metal ions (MI) and second the polyesterification between CA and ethylene glycol (EG). The effect of molar ratio CA:MI varying from 2-4 on structure, microstructure and electrical transport properties of LNMO have been investigated by constant the amount of EG. All samples show single perovskite phase with hexagonal structure and space group R3c after sintering at 800°C for 10h. Sample of molar ratio 2.5 is observed to possess smallest grain sizes which yield high resistivity value compared with others, is suggested to originate from the increase of tunneling barriers (grain boundaries). The large low field magnetoresistance (LFMR) of about ~ -16% at 0.1T and low temperature confirmed the important role of grain boundaries in the nanosized LNMO.

scholarly journals A Comparison of the Role of the Chelating Agent on the Structure of Lithium Conducting Solid Electrolyte Li1.4Al0.4Ti1.6(PO4)3: Pechini vs. Modified Pechini-Type Methods

Batteries ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 48
Author(s):  
Mohammad Reza Ghaani ◽  
Amir Masoud Mohtasebi ◽  
Razie Tajeri ◽  
Pirooz Marashi
Keyword(s):  
Citric Acid ◽  
Metal Ions ◽  
Electrochemical Impedance ◽  
Ethylenediaminetetraacetic Acid ◽  
Lithium Ion ◽  
Simultaneous Thermal Analysis ◽  
Chelating Agent ◽  
Molar Ratio ◽  
Complexing Agent ◽  
Solution Ph

In recent years, solid lithium-ion conductors have been widely studied because of their applications as electrodes and solid electrolytes in rechargeable lithium-ion batteries. Citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) were employed to synthesize the nanostructured NASICON-type Li1.4Al0.4Ti1.6(PO4)3 ceramic. The chelating agent, together with an ethylene glycol (EG) and the esterification agent were employed to form a network decorated with uniform dispersed metal ions under specific conditions: molar ratio [complexing agent/metal ions] = 1 and the molar ratio [EG/EDTA] = 6, whereas the solution pH was kept below 1. A well crystalline NASICON structure was formed following the heat treatment of the produced gel at 630 °C. Simultaneous thermal analysis (STA) revealed lower required temperature for pyrolysis and crystallization using EDTA. Powder X-ray diffraction (PXRD) showed the formation of larger crystallite size when citric acid was employed. The data from scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) have confirmed the higher apparent porosity and a larger proportion of grain boundaries in the case of EDTA-assisted synthesis.

Synthesis of Amorphous Al2O3-ZrO2 Powders Prepared by Citric Acid Gel Process

2012 ◽  
Vol 512-515 ◽  
pp. 73-76
Author(s):  
Yi Wang ◽  
Jia Chen Liu
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Thermal Behavior ◽  
Metal Ions ◽  
Sem Analysis ◽  
Molar Ratio ◽  
Total Metal ◽  
Acid Gel

AmorphousAl2O3ZrO2powders were synthesized by citric acid gel process. The effects of molar ratio of citric acid to total metal ions concentration and the calcined powders with CA/M=2:1 were investigated through XRD and SEM analysis. Thermal behavior of the dried gel with CA/M=2:1 was studied by DSC/TG. Amorphous Al2O3-ZrO2 powders with particle size of about 3μm were obtained.

Modified Technique for Measuring Platelet Aggregation

1997 ◽  
Vol 3 (3) ◽  
pp. 196-202 ◽  
Author(s):  
Alexander Kaplan ◽  
Svetlana Kaplan ◽  
Karen F. Marcoe ◽  
Lester R. Sauvage ◽  
William P. Hammond
Keyword(s):  
Platelet Aggregation ◽  
Citric Acid ◽  
Platelet Rich Plasma ◽  
Antiplatelet Agents ◽  
Current Approach ◽  
Molar Ratio ◽  
Maximum Height ◽  
Modified Technique ◽  
Aggregation Pattern

The turbidimetric method of Bom is the current approach for assessing the aggregation behavior of platelets. It has been of modest practical value, due to difficulty in standardizing laboratory techniques for plasma preparation and inadequate quantification of the aggregation process. We report a new technique of sedimented platelet rich plasma (SPRP) preparation that reduces the irregularities caused by factors associated with procuring and preparing blood samples and permits a more flexible protocol for laboratory practice. We quantified results with a platelet aggregation score, which is calculated by multiplying the ratio of the height of the initial wave of aggregation to the maximum height of the aggregation pattern by the total area under the aggregation curve and by the ratio of the whole blood platelet count and the number of platelets in the sample. Comparative analysis of platelet aggregation scores (n = 95) obtained with both plasma preparation techniques using a paired t test demonstrated no statistical differences ( t = 1.368, p = 0.174). To demonstrate the application of this modified method to evaluation of antiplatelet agents, the effects of aspirin and aspirin combined with citric acid on platelet aggregation were studied in vitro. The antiaggregatory effect of aspirin combined with citric acid was dependent on the pH and on their molar ratio, and was greater than the effect of aspirin alone. The SPRP protocol with platelet aggregation scoring methodology could be a valid alternative for measurement of the platelets' propensity to aggregate and the effect of antithrombotic treatments. Key Words: Platelet aggregation— Aspirin—Citric acid.

Study on desorption of Mn, Fe, and Mg from TMP and evaluation of the complexing strength of different chelating agents using side reaction coefficients 10th EWLP, Stockholm, Sweden, August 25–28, 2008

Holzforschung ◽  
2009 ◽  
Vol 63 (6) ◽  
Author(s):  
Kim Granholm ◽  
Pingping Su ◽  
Leo Harju ◽  
Ari Ivaska
Keyword(s):  
Citric Acid ◽  
Metal Ions ◽  
Chelating Agents ◽  
Side Reaction ◽  
Sodium Dithionite ◽  
Thermomechanical Pulp ◽  
Peroxide Bleaching ◽  
Ph Values ◽  
Reducing Environment ◽  
Ph Range

Abstract Chelation of thermomechanical pulp (TMP) was studied in this work. The desorption of Mn, Fe, and Mg due to their impact on peroxide bleaching was investigated. The desorption experiments were performed with EDTA, citric acid, oxalic acid, and formic acid as chelating agents at different pH. Chelation experiments with EDTA were carried out at pH 3–11. Sodium dithionite was used as the reducing agent in studying chelation with EDTA in a reducing environment. Mn was very effectively desorbed with EDTA from TMP at pH <10 and the reducing environment further improved the removal of all the studied metal ions from TMP with EDTA. Citric acid also removed Mn effectively from TMP at pH 5. The thermodynamic stability constants of different metal chelates do not present the correct picture of how strongly the metal ions are bound by the chelating agents in different conditions. But by means of the side reaction coefficients (α M(L)-coefficients) it is also theoretically possible to evaluate and compare the real binding strengths between the metal ions and different chelating agents at varying pH values and other solution conditions. In this study, a theory is given for the calculation of side reaction coefficients. Values of the α M(L)-coefficients, for the pH range 0–14, are presented for EDTA, DTPA, and also for some other new potential environmentally friendly chelating agents.

Study on Synthesis of Ester of Citric Acid and Palmityl Alcohol

2014 ◽  
Vol 900 ◽  
pp. 361-364
Author(s):  
Xiao Hui Wang ◽  
Xi Hua Du ◽  
Li Min Dong
Keyword(s):  
Reaction Time ◽  
Citric Acid ◽  
Cation Exchange ◽  
Sulfonic Acid ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Molar Ratio ◽  
Esterification Reaction ◽  
Process Conditions ◽  
Toluene Sulfonic Acid

Esters of Citric acid and palmityl alcohol were synthesized by esterification reaction under catalysis of cation exchange resin and P-toluene sulfonic acid respectively. The effects of amount of catalyst, ratio of raw materials, reaction time and temperature on the synthesis reaction were investigated . The experimental results showed that optimum of process conditions were 1:1~1:1.5 molar ratio of citric acid and palmityl alcohol, reaction temperature of 130~140°C, reaction time of 2 h. Conversion of palmityl alcohol were all more than 90% under 0.3% dosage using p-toluene sulfonic acid as the catalyst, or 0.5% dosage using 721 cation exchange resin with sulfonic acid type as catalyst. The synthesized product had good surface activity.

scholarly journals Synthesis, Characterization and Antimicrobial Activities of Mixed Ligand Complexes of Fe (II), Co(II), Ni(II) and Cu (II) Ions Derived from Imine of Benzidine and o-phenylenediammine

2020 ◽  
pp. 2762-2775 ◽  
Author(s):  
Hayder Hamied Mihsen ◽  
Suhad Kareem Abass ◽  
Maysaa Taqe Abed –Alhasan ◽  
Zainab M. Hassan ◽  
Ali Kreem Abass
Keyword(s):  
Metal Ions ◽  
Antimicrobial Activities ◽  
Fungal Species ◽  
Molar Ratio ◽  
Appreciable Change ◽  
Gram Positive Bacteria ◽  
Square Planar ◽  
Bacillus Spp ◽  
Ft Ir ◽  
Apparent Stability

Binuclear metal complexes of the metal ions Fe (II), Co (II), Ni (II) and Cu (II) were synthesized by the reaction of these metal ions with the imine of benzidine (H2L) as a primary ligand and o-phenylenediammine (OPD) as a secondary ligand  in a molar ratio of 2:2:1. The prepared complexes were characterized using CHN elemental analysis, FT-IR, UV-visible, molar conductivity, magnetic susceptibility and TGA-DTA thermogravimetric analysis. All the prepared complexes showed apparent stability and could be stored for months without any appreciable change. According to the results obtained by elemental and spectral analyses, a tetrahedral structure is suggested for all the prepared complexes, except for the copper complex which showed a square planar structure. The antimicrobial activities of these complexes were evaluated against Bacillus spp. (Gram-negative bacteria), Proteus spp. (Gram-positive bacteria) and Aspergillus niger (A. niger, a fungal species). The results showed that all the prepared complexes have no apparent effects on Bacillus spp. viability, whereas Proteus spp.  and A. niger were affected significantly.

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